#include<queue>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
char ss[100005];
int vis[100000];
int tot=0;
int n,m;
struct data{
	int l,r;
	friend bool operator<(data a,data b){
		return a.l<b.l;
	}
}e[50005];
int main(){
freopen("xxxx.in","r",stdin);
freopen("xxxx.out","w",stdout);
	scanf("%s",&ss[1]);
	n=strlen(&ss[1]);
	memset(vis,0,sizeof(vis));
	
	for(int i=1;i<=n;i++)
	{
		m=ss[i]-'a'+1;
		if(vis[m]>0){
			e[++tot]=(data){vis[m],i};
			vis[m]=0;
		}
		else vis[m]=i;
	}
	
	sort(e+1,e+1+tot);
	
	long long cnt=0;
	for(int i=1;i<=tot;i++)
	for(int j=i+1;j<=tot && e[j].l<e[i].r;j++)
	if(e[j].r>e[i].r) cnt++;
	
	cout<<cnt;	
	return 0;
}